Stock Based Compensation - Summary of Unvested Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Stock Based Compensation
Stock Options Outstanding - Beginning Balance	598,644
Stock Options Granted (in shares)	1,190,000	0
Stock Options Outstanding - Ending Balance	1,788,644
Weighted Average Exercise Price Outstanding - Beginning Balance	$ 16.00
Weighted Average Exercise Price - Granted	22.35
Weighted Average Exercise Price Outstanding - Ending Balance	$ 20.23
Aggregate Intrinsic Value	$ 11,399
Weighted Average Remaining Contractual Life (years)	9 years 7 months 24 days

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- Definition

Gross number of share options (or share units) granted during the period.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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- Definition

Number of non-vested options outstanding.

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No definition available.

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- Definition

Weighted average grant-date fair value of non-vested options outstanding.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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